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My shortblock is finally back from the machine shop and I'm getting excited!
It's a rebuilt Gen III motor
3.903 bore Weisco forged pistons with 5cc valve relief - decked and balanced.
Eagle forged I beam rods with arp 2000 rods bolts 6.125
Arp main rods / head bolts, cam sprocket
Melling performance 295 fuel pump with copo high pressure spring for high rpm road race / street application
The Cam is the Comp FSL (210/218)
Next to be installed is a set of CNC ported 243/799 heads
this is the engine modeling I’ve done, it assumes 91 octane fuel and full accessory load
In my experience with good data and analyzer is extremely accurate
The shop had a core available that I took advantage of. I was really on the fence between TPS and Thompson, but Thompson couldn't get me a Gen III core.
Thompson did a forged short block Gen 3 for me a little over a year ago. Even then, every recommendation was to build a Gen 4 but I wanted to keep the original DNA of the car. Definitely a bummer to hear that the Gen 3 blocks are getting scarce.
it is a damn bummer that aluminum gen 3 blocks are becoming scarce.
Originally Posted by dom04abp
Thompson did a forged short block Gen 3 for me a little over a year ago. Even then, every recommendation was to build a Gen 4 but I wanted to keep the original DNA of the car. Definitely a bummer to hear that the Gen 3 blocks are getting scarce.
Funny you should ask. Several LSX block manufacturers are about to find supply issues after a 100+ year old forge filed for bankruptcy last month. I know Dart is directly affected.
this is the engine modeling I’ve done, it assumes 91 octane fuel and full accessory load
In my experience with good data and analyzer is extremely accurate
This is gonna sound bad, but I don’t mean it to.
How does an almost stock cam fit in with expected high rpm track use? Also, on appearance, that cam doesn’t seem to align with 453 hp, granted head work more ci?
Again, not judging, so just trying to learn more about combinations..
The Cam is the Comp FSL (210/218)
Next to be installed is a set of CNC ported 243/799 heads
This is gonna be a nice street motor...
Well, he refers to it as being a street motor.
The FSL in the "Fifty States Legal" cam's title says a bunch about it. Some much bigger cams are smog legal when sniffed as it depends on the timing and a clean, isolated burn which doesn't pass any fresh fuel into the exhaust - as well as a proper tune. From experience with friends you can get a Jam Cam to pass CT emissions done right. If he's in CA (I didn't check location but it is presumed when someone says 'FSL' related to a build) maybe this one gets a pass?
This one's overlap is -22, so it has a very clean burn and ought to get good mpg.
Heads and cam together? CNC'd 243s generally being known for good low and mid lift prop this low lift cam up. He'll gain an easy average 35whp and 40wtq under the curve with peak gains being maybe.... 65whp and 45wtq gain over stock? This one should still be shifted at 6k, but the torque will at least keep building up to that point. Any gains here are almost exclusively derived from the increased flow of the heads which in this case benefit mid-range lift and that is where this stealth cam lives. It will sound as quiet as stock at idle.
Not bad for an around towner. It will act like a factory freak and no one will be the wiser. Add some long tubes and Titanium mufflers with a bypass kit and it will sound better at WOT while still being the quiet, calm cruiser.
All told, that is a lot of money invested for modest gains. But it will run happily forever just like stock. I might have opted for a Carb EO blower kit.
TUSC is right about my goals. This is going to be a fun street car that I essentially don't have to worry about. Is it a lot of money... yeah. My dad bought the car new and now it's mine, I really like it and plan to keep the car... forever. I'm in California, and with the CARB checking ECM tunes now, I have to be very careful that I'll have a car that can pass on a factory ECM tune. Yeah yeah, I know some tuners can dodge the ECM checks - for now. What if the state testing gets more sophisticated later?
I've built a lot of really hairy cars over the years. Frankly they've all gotten out of hand and become less streetable than I would have liked. I'm trying to stay reasonable.
RE: Camshaft, I've always maintained that, if you do the math, you really don't need a huge cam to go fast.
Look at the LS7 The factory cam is 211/230@0.050 with under .600 lift and an 121-LSA. The motor dependably makes power at 7000RPM. The LS7's 4" stroke should make the car more duration hungry, but it still makes power that high.
And the raw truth car guys hate to hear: Peak horsepower numbers don't matter. What matters is average torque across the usable RPM range.
All you really need to do is look at the nearly identical trap speeds of a '70 454 Vette with 450HP, compared to an 87 Corvette with a 240HP L98 . It's because the L98 makes torque, everywhere.
In a couple of years, I may decide to do an A&A Supercharger. The short block is built to withstand ~900HP... but that's a project for another day. This project already near the non-divorce-triggering budget redline.
You would very much like the cam I am designing for my 427 then. I have the Z06 with the 402 and future twin turbos which is going to be an overbuilt monster. But the 427 in the coupe.... having removed the supercharger, it leaves me with a clean, low miles car with amazing brakes and suspension. This is a true top grade C5 on that basis alone in terms of having such capabilities that it ought to outperform most C7s and C8s. I started out trying to compensate for the now NA 9.5 compression and ended up with a MASSIVE amount of torque wall low down and still having a sharp ramp up. Cool! This was done still with MPG and high overlap in mind with a slightly upgraded sound. But when I considered how I'd be driving it I changed my approach at the end and considered the limits of 315 tires as well as of comfortable driving. In this car, I do not want to have to think about feathering the throttle. I want this car to still be very fast, but fun in the sense of not having to think about it. Just put my foot down and go. My wanting it to also be a stable track event car is equally imposing and turns out to be in line with reducing that massive torque wall. I'm not out to win trophies. I am out to have fun with this car. So the final result is huge overlap, large LSA, slightly later IVC... all of which makes the low and mid rpm driving hopefully almost the same as a stock C6 Z06 experience. So I think I nailed that. But in this case with better cath heads and so much LSA and my duration and split.... the similarity with a stock LS7 exits once this one crosses 4500 and picks up a lot more air all the way to redline.
At least that's what I hope it does! Stock idle rpm and sound. Stock or better mpg. But it can lean into the wind up top and take advantage of those 3.73s. Most would not go for such a wildly mild cam.
The shortblock is here!
